The radio frequency (RF) spectrum is a finite resource that has been divided into RF bands and further divided into channels to prevent interference. Despite these divisions, interference may still occur. Some RF bands, such as the Unlicensed National Information Infrastructure (i.e., UNII) band or the Industrial, Scientific, and Medical (i.e., ISM) band, are especially prone to interference because the channels in these bands are available to a variety of users/applications.
To prevent interference on a channel, a wireless device may monitor the channel prior to and during use and take an action (i.e., tune channels) to avoid interference when interference is detected. This interference avoidance process is known as “dynamic frequency selection” (i.e., DFS).
A problem with DFS arises when a transmitter (e.g., a radar), operating on a first channel, “leaks” signals/noise into a second channel used by another device (e.g., wireless access point). When this occurs, the device operating on the second channel may unnecessarily determine that the transmitter (i.e., source) is operating on the same channel and begin DFS to prevent interference. This is problematic because a DFS resulting from a false determination of interference can causes communication delays and can limit the number of channels that appear available to the device.
A need, therefore, exists for a system and method to identify received signals as either “on-channel” (i.e., signals from a source operating on the operating channel) or “off-channel” (i.e., signals from a source operating “off-channel”). In certain embodiments, the identification may be used to mitigate unnecessary DFS operations performed by a wireless network apparatus (e.g., wireless access point) that communicates in a wireless local area network (i.e., WLAN).